In a YouTube video published in late November, He stunned the world with claims, which, if true, would be both historic and highly ethically questionable. Almost immediately, geneticists and others in the scientific community decried his research as premature and unethical, criticizing his methods and noting that not enough is known about the consequences of gene editing to pursue the practice at this time.

The co-inventor of CRISPR, Dr. Jennifer Doudna, issued a statement saying He and his colleagues should "fully explain their break from the global consensus that application of CRISPR-Cas9 for human germline editing should not proceed at the present time."

China's Southern University of Science and Technology, where He worked, said it had been unaware of the controversial research, and said it would open an investigation.

TheSouth China Morning Postwrote that He's whereabouts have not been known since last Wednesday. Other reports suggested He had been placed under house arrest by Chinese authorities. A spokeswoman with Southern University said He hadn't been placed under house arrest, but that she couldn't confirm details.

"Right now nobody's information is accurate, only the official channels are," the spokeswoman told the Morning Post, adding that she couldn't "answer any questions regarding the matter right now."

On Thursday, Huai Jinpeng, Party chief and executive vice chairman of the China Association for Science and Technology, said He's work was "extremely abominable in nature" and had "blatantly violated China's relevant laws and regulations."

Xu Nanping, a vice minister for science and technology, told state broadcaster CCTV that the work had "violated the ethical bottom line that the academic community adheres to. It is shocking and unacceptable." The China Association of Science and Technology has ordered an investigation into the matter.

Vanishing in China

Although it's still unclear why He is missing, it's worth noting that it's not uncommon for Chinese citizens, and even high-ranking officials, to go missing after slipping up in public or painting the government in a negative light.

More broadly, thousands of executives and officials have disappeared in recent years, likely as part of the anti-corruption campaign China began in 2012. The government says its aim is to purge from its ranks officials who abuse power or accept bribes. However, some critics say the primary goal of the program, which was expanded in March, is to allow Party leaders to get rid of opponents and keep everyone in ideological consensus.

Amnesty International has called the campaign, which can result in people being forcefully detained for months without access to a lawyer, as a "systemic threat to human rights in China."